SLVSGL4 September   2023 TPS1HTC30-Q1

PRODUCTION DATA  

  1.   1
  2. Features
  3. Applications
  4. Description
  5. Revision History
  6. Pin Configuration and Functions
    1. 5.1 Recommended Connections for Unused Pins
  7. Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 SNS Timing Characteristics
    7. 6.7 Switching Characteristics
    8. 6.8 Timing Diagrams
    9. 6.9 Typical Characteristics
  8. Parameter Measurement Information
  9. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Accurate Current Sense
      2. 8.3.2 Programmable Current Limit
        1. 8.3.2.1 Capacitive Charging
      3. 8.3.3 Inductive-Load Switching-Off Clamp
      4. 8.3.4 Inductive Load Demagnetization
      5. 8.3.5 Full Protections and Diagnostics
        1. 8.3.5.1 Short-Circuit and Overload Protection
        2. 8.3.5.2 Open-Load Detection
        3. 8.3.5.3 Thermal Protection Behavior
        4. 8.3.5.4 Overvoltage (OVP) Protection
        5. 8.3.5.5 UVLO Protection
        6. 8.3.5.6 Reverse Polarity Protection
        7. 8.3.5.7 Protection for MCU I/Os
      6. 8.3.6 Diagnostic Enable Function
    4. 8.4 Device Functional Modes
      1. 8.4.1 Working Mode
  10. Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Dynamically Changing Current Limit
      3. 9.2.3 Application Curves
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
        1. 9.4.2.1 Without a GND Network
        2. 9.4.2.2 With a GND Network
        3. 9.4.2.3 Thermal Considerations
  11. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documentation
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Support Resources
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary
  12. 11Mechanical, Packaging, and Orderable Information

パッケージ・オプション

メカニカル・データ(パッケージ|ピン)
サーマルパッド・メカニカル・データ
発注情報

Dynamically Changing Current Limit

The current limit threshold can be changed dynamically by altering the resistance going from the current limit pin to the ground of the device on the fly. This alteration allows the system to have a different current limit for start-up, when there can be significant inrush current, and during normal operation. The way this is commonly done is by putting two resistors in parallel on the ILIM pin and having a switch to enable or disable one of the resistors. This set-up can be seen in Figure 9-2. Alternatively, a digital potentiometer can be used to adjust the impedance on the ILIM pin on the fly. Care must be taken so that the capacitance on the ILIM pin is below approximately 100 pF to keep the current regulation loop stable. The most common application where this feature is useful is capacitive loads.

GUID-20210121-CA0I-HMPP-RMHZ-CPTBHHK38VDS-low.svg Figure 9-2 Dynamic Changing Current Limit Setup

In a capacitive charging case, the initial current to charge the capacitor is the inrush current. Depending on the system requirements, dynamically changing the current limit can help either charge up a capacitor faster or charge up a larger capacitor. To allow a higher inrush level of current through in the beginning, the switch can be closed making the current limit be according to the equation below.

Equation 14. ILIM2 = KCL(RILIM1 + RILIM2) / (RILIM1 × RILIM2)

When the inrush event is over and the output voltage is charged up, the switch opens and the current limit is just the RILIM1 equivalent level. This timing can be seen in Figure 9-3.

GUID-20230921-SS0I-3QK7-02JF-NK59NW3XSKC7-low.svg Figure 9-3 Capacitive Charging Changing Current Limit

Alternatively, if the switch is open, the current limit starts out at a lower value and then the switch can be closed when the capacitance gets charged up. This lower current limit level allows higher value capacitance to be charged up. The timing diagram can be seen in Figure 9-4.

GUID-20230921-SS0I-CV4P-BDHR-3TS3XGJPBLPM-low.svg Figure 9-4 Large Capacitive Charging Changing Current Limit